Multiple sampler circuit



Jan. 13, 1970 G. \(ARGIU MULTIPLE SAMPLER CIRCUIT Filed Feb. 4, 1966 256SHE? PM INVENTOR GIACOMO VARGIU BY Q .C'

ATTORNEY United States Patent 3,490,047 MULTIPLE SAMPLER CIRCUIT GiacomoVargiu, 150 Doherty, Redwood City, Calif. 94061 Filed Feb. 4, 1966, Set.No. 525,048 Int. Cl. H03k 5/159 US. Cl. 328-451 3 Claims ABSTRACT OF THEDISCLOSURE A high bandwidth signal sampler which separates the signalinto two phase related signals and samples each of them at a selectedrate, but at times which are delayed by the phase separation of thesesignals.

This invention relates to signal samplers and has as its main object theprovision of a circuit which has higher bandwidth than a conventionalsignal sampler when operated at a selected signal sampling rate.

This is accomplished according to the illustrated embodiment of thepresent invention by separating the signal to be sampled into at leasttwo phase-related signals and by sampling each of them at the selectedrate but at times which are delayed by the phase separation of thesesignals.

In the drawing which shows a schematic diagram of the circuit of thepresent invention, a phase separator 9 is connected to receive signal tobe sampled from a source 11 for producing at least two signals at theoutputs 13, 15 which are separated in phase by uniform increments butwhich have the same wave shape as the applied signal. Each of theseoutput signals is applied to a sampler 17, 19 which is renderedmomentarily conductive by a sample signal applied thereto from thesample signal generator 21. These sample signals are also separated intime corresponding to the relative phase shift of the signal to besampled appearing at the outputs 13, 15 of phase separator 9. Thisproduces sample pulses having amplitudes related to the amplitude of theapplied signal at the sample instant. The sample pulses from the twosamplers 17, 19 are combined in network 23 to produce a train of samplepulses at the input of stretcher circuit 25 which includes twice thesample information per cycle of signal from source 11 as is availableusing conventional sampling techniques and which contains predominantlyonly odd harmonics of the frequency of the signal from generator 21.

This multiple sampling techniques may be further ex tended, for example,by sampling at four equally-spaced intervals. There, the applied signalmay be selectively transformed as by integration or differentiation toprovide a change of signal amplitude per unit time about the additionalsample points t and L, which is normally approximately equal to thechange of signal amplitude per unit time about the sample points t and tThis provides a plurality of sample pulses per cycle of applied signalhaving approximately amplitudes which may vary about a normal value inresponse to phase error and noise at the sampling instant. The increasein sample information per cycle of applied signal results in more rapidresponse of the output of the pulse stretcher circuit 25 toperturbations in the applied signal from source 11 because the nextsample is derived after a time interval which is considerably shorterthan the time interval after which another sample would be taken byconventional sampling methods. This produces an effectively higheroperating bandwidth for use, as an example, in a phase-locked systemwith concomitant wider capture range. Improved filtering capabilitiesalso result from the absence of even harmonics in the combined samplepulses from at least two samplers 17, 19. Such a phase-locked systemwith the sample signal generator 21 operating as the reference frequencyis shown as a feedback circuit connected through switches 20, 22 fromthe output of the pulse stretcher 25 (which maintains a steady outputbetween sample pulses at a value related to the amplitude of a precedingpulse), through a control circuit 27 to the source 11 to maintain thephase of signal from source 11 in a fixed relationship to the signalsfrom generator 21. Utilization circuit 29 operates on the output signalfrom stretcher circuit 25, which output signal is proportional to thephase difference between the signal to be sampled from source 11 and thesignal from generator 21 during proper phase-locked operation of thecircuit shown. Of course, the signal sampler of the present inventionmay also be used in other sampler circuits with similar advantages ofgreater sample information .per cycle of applied signal and widereffective operating bandwidth.

I claim:

1. Signal sampling apparatus comprising:

a plurality of samplers, each having an output, an applied signal inputand a control signal input and operative to conduct momentarily inresponse to a signal applied to the control signal input thereof forproducing a sample pulse at the output thereof having an amplituderelated to the amplitude of signal applied to the applied signal inputthereof at the moment of sampler conduction;

circuit means having an input and having a plurality of outputsconnected for applying to the applied signal inputs of the samplers anin-phase signal and an out-of-phase signal which have time-varyingamplitudes that are proportional at every instant of time to thetime-varying amplitude during a cycle of signal appearing at the inputof said circuit means;

control signal generating means connected to the control signal inputsof said samplers for applying control signals to said samplers innon-simultaneous succession to render the samplers momentarilyconductive in sequence only at substantially the same single portion ofthe cycle of the phase-separated signals applied to the applied signalinputs of said samplers; and

means connected to the outputs of said samplers to produce an outputsignal related to the combination of signals appearing at the outputs ofsaid samplers.

2. Signal sampling apparatus asin claim .1 wherein:

the control signal generating means applies control signals to each ofthe samplers at times during a cycle of the signal at an applied signalinput of a sampler which are separated by equal increments for renderingeach of the samplers momentarily conductive during the portions of thecycles of signals at the applied signal input of each of the samplersfor which the rates of change with time of the amplitudes of suchapplied signals are substantially equal.

3. Signal sampling apparatus as in claim 2 comprising:

a pair of samplers;

.3 said circuit means produces a pair of out-of-phase signals at theoutputs thereof; and said control signal generating means appliescontrol signals to said samplers in alternating sequence to render saidsamplers alternately conductive in opposite phase relationship.

References Cited UNITED STATES PATENTS Cherry 328-l51 Thomas 73462Coates 328--151 Boensel 328167 US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, Dat dJanuary 13,

Inventor(s) G. Vargiu It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

In column 1, below the title, after the inventor's name, "150 Doherty"should be deleted; after "California" delete 94061 and substituteassignor to Hewlett- Packard Company, Palo Alto, Calif. a corporation ofCalifornia SIGNED KND SEALED JUL 141970 G Axum:

Edward M. Fletcher, In ull E. sum, m Atbesfing Officer mmission" ofPatents

